Reliability Model for Pavement Performance

Abstract

A simulation model to calculate the reliability/performance of pavements is developed. The computer program, Reliability Analysis and Performance of Pavements (RAPP‐I), employs Monte Carlo simulation techniques to solve the design equations (e.g., AASHTO, Premium) in which all of the design variables are assumed to be probabilistic and normally distributed. RAPP‐I, in conjunction with the respective design model, calculates the present serviceability index (PSI) of pavements in one‐year increments. In addition to uncertainties attributable to the design factors, errors due to idealization of the model are included in the PSI calculation. By comparing the computed PSI with the terminal PSI, assuming that both are normally distributed, standard probabilistic techniques are employed for calculating pavement reliability. An expression for calculating the “expected” life of pavements, employing the reliabilities at various ages, is proposed. The expected life is found to be a convenient measure for comparing the performance of various pavement design features.